Tanager Lake (DNR ID: 27-0141)
Sampling Location GPS Coordinates: 44.9613N, -93.5613W Surface Area: 74 acres Max. Depth: 20 ft
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Tanager Lake is located near the city of Wayzata. Head east on Minnetonka Blvd, and turn left on Co Rd 101 S. Turn right at Grays Bay Blvd and enter the Grays Bay Marina and public access on the left side of the road.
Tanager Lake is on Lake Minnetonka which is a class 2B lake protected for aquatic life and recreation. Water quality information is available beginning in 2000. MCWD staff have been monitoring the site on Tanager Lake on a bi-weekly basis from the time of ice out (April) to the time of fall mixing (mid-October) since 2006.
See Previous Reports.
Monitoring season started in late April and ended in late October. A YSI multi-probe sonde was used to measure dissolved oxygen (DO), temperature (oC), pH, and specific conductivity (µS/cm) at each meter depth from the water surface to the bottom. Additionally, water samples were collected within the first two meters of the surface with a 2-meter composite sampling tube. Samples one meter above the bottom were collected with a Van Doran water sampler. Surface sample were analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), total nitrogen (TN), where the bottom samples were analyzed for TP and SRP. Surface concentrations of chlorophyll-a were also analyzed and measurements of Secchi disc depth were recorded.
| 2009 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | 0.4 - 1.7 | 0.8 | 64 | D |
| Surface TP (µg/L) | 57 - 107 | 85.2 | 68 | D |
| Chlorophyll-a (µg/L) | 18 - 150 | 77.3 | 73 | D |
| Overall Score | 69 | D |
The following summary refers to Figure 3.49 (a-d).
- Secchi disk depth increased to 1.0 m to 2.5 m by late May then decreased to 0.7 m by late June. Secchi disk depth increased to 1.6 in early July, but declined for the remainder of the season (standard > 1.4 m).
- Chlorophyll-a concentrations decreased from 31 μg/L to 12 μg/L from late April to early May, and then increased to 150 μg/L by early August (standard < 14 μg/L). Chlorophylla concentrations declined for the remainder of the season.
- Surface TP concentrations decreased from 101 μg/L to 79 μg/L by early May and then increased to 124 μg/L by late May (standard < 40 μg/L). From early June to early August concentrations gradually increased to 107 μg/L. The rest of the season
concentrations fluctuated between 84 μg/L and 100 μg/L. Surface SRP concentrations were below detection limit (< 0.005 μg/L) for the season, except from late April to early May, early June and from late August to early October. - Bottom TP concentrations decreased from 151 μg/L to 50 μg/L from late April to late May, then increased to 206 μg/L by early June. TP concentrations declined later in June and then remained above 100 μg/L until the end of the season. Bottom SRP concentrations increased from late April to early June from < 0.005 μg/L to 125 μg/L. The remainder of the season, SRP concentrations fluctuated between < 0.005 μg/L and 58 μg/L.
Lake Grades and Historical Monitoring Summaries
When available, previous reports are linked to applicable year. Additional lake data previous to 2007 may be available in the applicable year's hydrodata report. If you have additional questions or you are looking for specific information please contact MCWD's Water Quality Staff.
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